non-REM Sleep May Renormalize Synapse Strength

(not yet studied in mammals)

The ratio of the strength of a synapse between neurons and the total potential (from all incoming synapses) needed to activate a neuron may be all that figures; the absolute values may not be important (this is the basis for computer neural networks, though temporal effects, firing rates, and who knows what else also matter in real brains).

So you can renormalize (multiply by some constant 1) and see almost no difference except for perhaps greater susceptibility to noise. But at least the amount of physical material needed is smaller, and the energy needed is smaller. It’s more efficient.

In flies and other simple animals studied so far, this definitely happens during sleep. Maybe it happens in humans also. (remains to be studied).

In any case, be careful committing to some REM-sleep only 3hr/day-with-naps sleep schedule, just because you may feel fine at first, when the exact utility of non-REM sleep isn’t completely known.